Fuel system question

[Dave B]

After dealership replaced injection pump I having even more starting problems. Cranking time keeps increasing until the starter will kick out before my 03 starts. If I crack bleeder screw and pump primer I get fuel on first pump. Uning Kennedy Diesel vacum gage I had 3" of vacum while cranking. Increased to 5" when truck started and dropped back to 3" at idle. If I pump primer to 7.5 psi(gage max.) pressure will immeadiately drop to almost 0.

Does this sound like a air leak in the system somewhere? The problem has gotten worse since the injection pump was replaced. Unlike the techs at the Chevy dealership, tech at the GMC dealership doesn't think it is a fuel restriction(plugged filter) problem. I'm going to try the GMC dealership now. I've had my truck in to the Chevy dealership at least 6 times for the same problem with no resolution. Problem is with GM not letting GMC warrenty any problem they might find.

[madmatt]

fuel in the oil? ever had the injectors replaced?

[Dave B]

Never any fuel in oil. NO injectors have been replaced. Until it quit starting at all 3wks ago, dealership always insisted it was fuel filter. When it wouldn't start they said it failed several diagnostic tests on the injection pump. They called tech support and replaced pump under warrenty. Within a couple of hundred miles of getting it back it is starting hard again. I don't think I'm willing to take it back to that dealership. Their Duramax tech just doesn't seem to be able to fix anything unless it's very obvious or there is a error code. I may be forced to buy a Ford or a Dodge if the GMC dealership doesn't get it. At least they might have techs that can fix something!

[Jim Brzozowski]

Dave, just for grins the next couple of time you go out to start the truck, pop the fuel filler cap off and put it back on and see if maybe its not venting properly. Might just be the fuel cap.
My 02 never has cranked for more than 3 seconds without starting, hot or cold.

[Kennedy]

The pessimist in me leans towards injector issues and the inability for the pump to hit the 5,000+ psi required to light the engine off.

Try pumping the primer up hard with the bleeder closed and see if this helps.

[Dave B]

I've tried venting fuel cap and pumped the primer pump as tight as I can. No help in the past. Guess I'll try GM customer service. My Duramax has left me set again this morning. I'll be down until at least next week. GMC dealers Dmax tech is on vaction and I don't I'm willing to go to the Chevy dealer again.